| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent mis-synchronization by stopping word synchronization when exclusive OR between low-order group signals of adjacent channels is coincident and shifting a window signal by one bit for each prescribed period so as to take frame synchronization. SOLUTION: Exclusive OR circuits 41 , 42 calculate arithmetically exclusive OR between adjacent low order group signals DATA1, 2 and DATA2, 3 and provide the output of the arithmetic result to AIS detection signals AIS DET 12, 23. As a result, when the patterns of both the arithmetic values are coincident, a window generating section 3 releases a 2nd inhibit circuit 26 to stop the word synchronization. Furthermore, the width of the window signal generated in the timing generating section 21 is changed into the same signal length as the frame synchronization word and a 1-bit inhibit circuit 23 shifts the window signal by one bit. A frame synchronization word detection section 12 detects the coincidence between the window signal and the frame synchronization word, a frame synchronizing signal is outputted. Thus, the generation of mis- synchronization is prevented.</p> |
